Laminate-Type Actuator with Segmented Meander Electrodes
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Solution Overview
Problem
Conventional laminate-type actuators suffer from low volume efficiency and reliability due to cracking and electrode damage when flattened from a cylindrical shape, as the winding core interferes with operation and expansion, and thick electrodes inhibit movement.
Innovation Solution
A laminate-type actuator design featuring a tubular structure with flat and curved portions, where the electrostrictive material layer is wound with electrodes sandwiched between, and a method to deform the cylindrical laminate by external force and heat to create spaces that prevent electrode cracking, enhancing volume efficiency and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the cylindrical laminate is flattened to improve volume efficiency, then volume efficiency is improved, but electrode cracking and damage occur reducing reliability
Solution Approach 1:
The patent segments the electrode into multiple independent meander-shaped patterns rather than a single continuous electrode. This segmentation allows each electrode segment to independently accommodate the bending and deformation during actuator operation, preventing crack propagation that would occur in a continuous electrode structure when the cylindrical laminate is flattened.
Solution Approach 2:
The patent employs meander-shaped (curved) electrode patterns instead of straight linear electrodes. The curved meander configuration allows the electrode to flex and deform elastically during the expansion and contraction cycles of the actuator, accommodating the flattening process and operational deformations without causing crack formation in the electrode material.
2Ease of operation
If the winding core is removed to enable actuator operation, then actuator operation is enabled, but the laminate structure becomes unstable during deformation
Solution Approach 1:
The patent applies preliminary actions by pre-forming the electrodes into meander patterns and pre-laminating the electrostrictive material layers with electrodes in a controlled manner before the flattening process. This preliminary structuring ensures that the laminate maintains its compositional stability and layer alignment even after the winding core is removed and during subsequent deformation operations.
3Strength
If electrode thickness is increased to prevent cracking, then electrode strength is improved, but expansion and contraction are inhibited
Solution Approach 1:
The meander-shaped curved electrode pattern provides mechanical flexibility and elasticity, allowing thin electrodes to withstand deformation stresses without cracking. The curved geometry distributes stress along the electrode length, enabling thin electrodes to maintain both strength and flexibility, thus preventing crack formation while preserving the actuator's expansion and contraction capabilities.
Solution Approach 2:
The patent changes the geometric parameters of the electrode from straight linear forms to meander-shaped curved patterns. This parameter change in electrode geometry fundamentally alters the stress distribution and deformation characteristics, allowing thin electrodes to achieve the necessary durability and crack resistance without increasing electrode thickness, thereby maintaining full expansion and contraction displacement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design improves volume efficiency and reliability by preventing electrode damage and allowing for continuous operation without cracking, while maintaining high electric efficiency and simplicity in production.
Implementation Method 1
a material layer which expands and contracts by application of electric voltage or electric field
Implementation Method 2
the cylindrical and tubular laminate thus obtained (which consists of the electrostrictive material layer and the electrodes on both of its surfaces) is pressed in a direction perpendicular to its axis to deform it into an elliptical shape
Data Source
AI summary
A laminate-type actuator including a laminate wherein an electrostrictive material layer is wound and laminated in a form of a tube together with first and second electrodes sandwiching the electrostrictive material layer therebetween is provided with high volume efficiency and high reliability. The tubular laminate includes a pair of flat portions facing each other and a pair of curved portions interconnecting the pair of flat portions circumferentially and specifying spaces inside the curved portions. In a cross-section perpendicular to an axis of the laminate, an outer width formed by the pair of flat portions is smaller than an outer width of each of the curved portions, and a distance between the pair of flat portions is smaller than an inner width of each of the curved portions.